ASoC: qcom: Add helper for allocating Soundwire stream runtime

Newer Qualcomm SoC soundcards will need to allocate Soundwire stream
runtime in their startup op.  The code will be exactly the same for all
soundcards, so add a helper for that.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20231128165638.757665-1-krzysztof.kozlowski@linaro.orgSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/qcom/sdw.c

 // SPDX-License-Identifier: GPL-2.0
-// Copyright (c) 2018, Linaro Limited.
+// Copyright (c) 2018-2023, Linaro Limited.
 // Copyright (c) 2018, The Linux Foundation. All rights reserved.
 
 #include <dt-bindings/sound/qcom,q6afe.h>
@@ -7,6 +7,49 @@
 #include <sound/soc.h>
 #include "sdw.h"
 
+/**
+ * qcom_snd_sdw_startup() - Helper to start Soundwire stream for SoC audio card
+ * @substream: The PCM substream from audio, as passed to snd_soc_ops->startup()
+ *
+ * Helper for the SoC audio card (snd_soc_ops->startup()) to allocate and set
+ * Soundwire stream runtime to each codec DAI.
+ *
+ * The shutdown() callback should call sdw_release_stream() on the same
+ * sdw_stream_runtime.
+ *
+ * Return: 0 or errno
+ */
+int qcom_snd_sdw_startup(struct snd_pcm_substream *substream)
+{
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct snd_soc_dai *cpu_dai = snd_soc_rtd_to_cpu(rtd, 0);
+	struct sdw_stream_runtime *sruntime;
+	struct snd_soc_dai *codec_dai;
+	int ret, i;
+
+	sruntime = sdw_alloc_stream(cpu_dai->name);
+	if (!sruntime)
+		return -ENOMEM;
+
+	for_each_rtd_codec_dais(rtd, i, codec_dai) {
+		ret = snd_soc_dai_set_stream(codec_dai, sruntime,
+					     substream->stream);
+		if (ret < 0 && ret != -ENOTSUPP) {
+			dev_err(rtd->dev, "Failed to set sdw stream on %s\n",
+				codec_dai->name);
+			goto err_set_stream;
+		}
+	}
+
+	return 0;
+
+err_set_stream:
+	sdw_release_stream(sruntime);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(qcom_snd_sdw_startup);
+
 int qcom_snd_sdw_prepare(struct snd_pcm_substream *substream,
 			 struct sdw_stream_runtime *sruntime,
 			 bool *stream_prepared)

sound/soc/qcom/sdw.h

@@ -6,6 +6,7 @@
 
 #include <linux/soundwire/sdw.h>
 
+int qcom_snd_sdw_startup(struct snd_pcm_substream *substream);
 int qcom_snd_sdw_prepare(struct snd_pcm_substream *substream,
 			 struct sdw_stream_runtime *runtime,
 			 bool *stream_prepared);